1. Bringing a cash gift. A monetary gift? Totally cool. But a gift made out in $20 bills? Not so cool. If your envelope gets lost, your gift will be gone for good. Instead, play it safe with a check!

2. Getting smashed…at cocktail hour. You may only be going to the wedding for the open bar (uh…and to celebrate the happy couple, of course), but that doesn’t mean it’s a good idea to get trashed. Sure, have your fun—but pace yourself. Wedding receptions can be several hours long. Remember that it’s a marathon, not a sprint.

3. Wearing heels to an outdoor wedding. If you want to wear your favorite stilettos, be prepared to sink right into the lawn—not exactly the sexy look you were going for. Opt instead for wedges or fancy flats. Can’t imagine going without pumps? Get heel protectors to stop yourself from toppling over.

4. Getting a phone call during the vows. Even if the couple didn’t specify that they’re having an “unplugged” wedding, you’re smart enough to silence your phone during the ceremony. Instead, you can join the crowd of cringes when the bride’s cousin’s phone blares an embarrassing ring tone.

5. Showing up late. A wedding isn’t just a casual party, and being late is far from fashionable. In fact, being early is better — if the invitation says the ceremony starts at 2:30pm, plan to be at the venue by 2:15pm.

6. Bringing an uninvited +1. A guest brining a date who wasn’t invited is basically every couple’s worst nightmare. Seriously, it’s not that hard to tell if you’re allowed to bring a date. Did your invitation say “Your Name & Guest”? If not, you’ll be flying solo. No negotiations!

7. Wearing white. Would you want a guest wearing white at your wedding? Didn’t think so. Don’t play games, either. If you’re thinking to yourself, “But it’s just a little bit of white,” or “Well, it’s not all white,” just don’t go there.

When it comes down to it, just be polite and use common sense, and you’ll be the perfect guest.